<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div>
        <div></div>
        <div>
            c1
        </div>
    </div>
    <div>
        <div></div>
        <div id="i1">
            c2
        </div>
    </div>
    <div>
        <div></div>
        <div>
            c3
        </div>
    </div>
</body>
</html>